Light can trigger coordinated, wave-like motions of atoms in atom-thin layers of crystal, scientists have shown. The waves, called phonon polaritons, are far shorter than light waves and can be "tuned" to particular frequencies and amplitudes by varying the number of layers of crystal, they report.
The huge surface area and strong interactions between graphene layers causes facile “...
A team of researchers has developed a material that could help prevent blood clots associated...
Last year, a physicist and a mechanical engineer at Northeastern Univ. combined their expertise to integrate electronic and optical properties on a single electronic chip, enabling them to switch electrically using light alone. Now, they have built three new devices that implement this fast technology: an AND-gate, an OR-gate and a camera-like sensor made of 250,000 miniature devices.
Every second, your computer must process billions of computational steps to produce even the simplest outputs. Imagine if every one of those steps could be made just a tiny bit more efficient. A Northeastern Univ. team has developed a series of novel devices that do just that. The team combined their expertise to unearth a physical phenomenon that could usher in a new wave of highly efficient electronics.
Researchers at Argonne National Laboratory in collaboration with scientists at Northwestern Univ. are the first to grow graphene on silver which, until now, posed a major challenge to many in the field. Part of the issue has to do with the properties of silver, the other involves the process by which graphene is grown.
Researchers have devised a way of making tiny holes of controllable size in sheets of graphene, a development that could lead to ultra-thin filters for improved desalination or water purification. The team of researchers succeeded in creating subnanoscale pores in a sheet of the one-atom-thick material, which is one of the strongest materials known.
Previous efforts to create graphene nanoribbons followed a top-down approach, using lithography and etching process to try to cut ribbons out of graphene sheets. Cutting ribbons 2 nm-wide is not practical, however, and these efforts have not been very successful. Now, a research team has developed a chemical approach to mass producing these graphene nanoribbons. This process that may provide an avenue to harnessing graphene's conductivity.
A single-walled carbon nanotube grows from the round cap down, so it’s logical to think the cap’s formation determines what follows. But according to researchers at Rice Univ., that’s not entirely so. Theoretical physicist Boris Yakobson and his Rice colleagues found through exhaustive analysis that those who wish to control the chirality of nanotubes would be wise to look at other aspects of their growth.
On a pound-per-pound basis, carbon nanotube-based fibers invented at Rice Univ. have greater capacity to carry electrical current than copper cables of the same mass, according to new research. While individual nanotubes are capable of transmitting nearly 1,000 times more current than copper, the same tubes coalesced into a fiber using other technologies fail long before reaching that capacity.
An international team has recently unveiled a superconducting pairing mechanism in calcium-doped graphene. The pairing, which was using a angle-resolved photoemission spectroscopy method, is important because graphene is easily doped or functionalized with chemicals, allowing scientists to more fully explore the nature of superconductivity.
An international team of researchers from France and the United States have devised an entirely new way to synthesize graphene ribbons with defined, regular edges, allowing electrons to flow freely through the material. Demonstrating this phenomenon at room temperature, the material was shown to permit electron flow up to 200 times faster than through silicon.
Using electrons more like photons could provide the foundation for a new type of electronic device that would capitalize on the ability of graphene to carry electrons with almost no resistance even at room temperature—a property known as ballistic transport. Research reported that electrical resistance in nanoribbons of epitaxial graphene changes in discrete steps following quantum mechanical principles.
By sandwiching a biological molecule between sheets of graphene, researchers at the Univ. of Illinois at Chicago have obtained atomic-level images of the molecule in its natural watery environment. Researchers typically rely on relatively thick windows of silicon nitrate to protect specimens in a vacuum environment of an electron microscope, but the atomically-thin graphene sheets promise a major improvement.
Scientists have used a particle physics theory to describe the behavior of particle-like entities, referred to as excitons, in two layers of graphene. The use of equations typically employed in high-energy physics has prompted the authors to suggest a design for an experimental device relying on a magnetically tunable optical filter that could verify their predictions.
Perfect sheets of diamond a few atoms thick appear to be possible even without the big squeeze that makes natural gems. Scientists have speculated about it and a few laboratories have even seen signs of what they call diamane, an extremely thin film of diamond that has all of diamond’s superior semiconducting and thermal properties.
Plasmonic nanoparticles developed at Rice Univ. are becoming known for their ability to turn light into heat, but how to use them to generate electricity is not nearly as well understood. Scientists at Rice are working on that, too. They suggest that the extraction of electrons generated by surface plasmons in metal nanoparticles may be optimized and have measured the time plasmon-generated electrons take moving from nanorods to graphene.
Scientists at the U.S. Naval Research Laboratory have created a new type of tunnel device structure in which the tunnel barrier and transport channel are made of the same material, graphene. Their work shows the highest spin injection values yet measured for graphene, opening an entirely new avenue for making highly functional, scalable graphene-based electronic and spintronic devices a reality.
Researchers are proposing a new technology that might control the flow of heat the way electronic devices control electrical current, an advance that could have applications in a diverse range of fields from electronics to textiles. The concept uses tiny triangular structures to control phonons, quantum-mechanical phenomena that describe how vibrations travel through a material's crystal structure.
Graphene, a sheet of carbon one atom thick, may soon have a new nanomaterial partner. In the laboratory and on supercomputers, chemical engineers have determined that a unique arrangement of 36 boron atoms in a flat disc with a hexagonal hole in the middle may be the preferred building blocks for “borophene.”
“Cool it!” That’s a prime directive for microprocessor chips and a promising new solution to meeting this imperative is in the offing. Researchers with the U.S. Dept. of Energy’s Lawrence Berkeley National Laboratory have developed a process-friendly technique that would enable the cooling of microprocessor chips through carbon nanotubes.
Sometimes solving a problem doesn’t require a high-tech solution. Sometimes, you have to look no farther than your desktop. Three students from Northwestern Univ.’s McCormick School of Engineering have proven that pencils and regular office paper can be used to create functional devices that can measure strain and detect hazardous chemical vapors.
As part of his PhD, postdoctoral research fellow Dr. Daniel Tune in Australia has designed a computer modelling system that shows which combination of carbon nanotubes absorb the most sunlight, therefore providing the most energy. In 2011, researchers in the U.S. successfully fabricated a solar cell using carbon nanotubes, but there are more than 70 different types of carbon nanotube that could be used in such solar cells.
Researchers in California have created tactile sensors from composite films of carbon nanotubes and silver nanoparticles similar to the highly sensitive whiskers of cats and rats. These new e-whiskers respond to pressure as slight as a single Pascal, about the pressure exerted on a table surface by a dollar bill.
A new approach to harvesting solar energy, developed by Massachusetts Institute of Technology researchers, could improve efficiency by using sunlight to heat a high-temperature material whose infrared radiation would then be collected by a conventional photovoltaic cell. This technique could also make it easier to store the energy for later use, the researchers say.
A collaboration of researchers has discovered that sodium bismuthate can exist as a form of quantum matter called a 3-D topological Dirac semi-metal (3DTDS). This is the first experimental confirmation of 3-D Dirac fermions in the interior or bulk of a material, a novel state that was only recently proposed by theorists. It is a natural counterpart because of its magnetoresistive properties.
Rice Univ. scientists have found they can control the bonds between atoms in a molecule. The molecule in question is carbon-60, also known as the buckminsterfullerene and the buckyball, discovered at Rice in 1985. The scientists found that it’s possible to soften the bonds between atoms by applying a voltage and running an electric current through a single buckyball.
Using an approach akin to assembling a club sandwich at the nanoscale, NIST researchers have succeeded in crafting a uniform, multi-walled carbon nanotube-based coating that greatly reduces the flammability of foam commonly used in upholstered furniture and other soft furnishings. The flammability of the nanotube-coated polyurethane foam was reduced 35% compared with untreated foam.
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